Aircraft: EMB ERJ 170/175 ER/LR
Phase of flight: Cruise
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Speed All Types; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

We were cruising at FL370 when we received the EICAS message 'BLEED APU LEAK' even though the APU was not running. We ran the QRH but the message did not go away so we descended to FL310 and shut off the cross bleed; and bleed 1 per the QRH. We were in cruise for nearly 20 minutes when I noticed white smoke coming from under the CA (Captain) display units. Just as I saw the smoke; I smelled it. The CA had also seen and smelled smoke and we both commented on it at the same time. The CA used the EMER call button to contact the FAs (Flight Attendants). Both FAs immediately commented on the smoke smell when they answered. We told them we were [advising ATC] and hung up. Both of us donned our O2 masks right away and I radioed Center. The CA was flying and started an [expedited] decent. I saw ZZZ was only about 20 miles south west of our position. We told ATC to show that as our destination. As I was ACARS'ing dispatch; we received a frequency change so I dropped the message in the free text box without sending it to put in the frequency and then input the destination to get pointed in the correct direction. By the time I got back to it; Dispatch had messaged us saying that company in ZZZ was expecting us and to not worry about replying. Coming through 10;000 ft.; I pulled the mask away from my face to see if the smoke smell was still strong. It was not; so we decided to take the masks off and continued in. In an attempt to slow up further and increase our rate of descent; we dropped the gear at 250 kts. and the warning tape came up. We over sped the gear by maybe 2 kts. for less than a couple seconds. Once on the ground; we asked the FA's if there was still smoke in the back. They said there was a faint smell and no visible smoke. We made the decision not to evacuate and parked at a gate. The entire event lasted 13 minutes from starting the descent to landing. While at in cruise at FL370; we received the ICAS message Bleed APU Leak. We completed the QRH procedure all the way through. We had descended to FL310 and remained there for just under 15 minutes when we noticed smoke in the cockpit. The smoke was gray-ish/white-ish in color and was accompanied by a very pungent smell. The FO (First Officer) and myself very quickly put on our oxygen masks and I pushed the cabin emergency call button. The FA's (Flight Attendants) both confirmed the smell but did not see any smoke. Later; the FA's told me they were looking for smoke moments before we called them and after we called them; and several passengers started to ask the FA about the smell. With oxygen masks on; communication established; and smoke in the air; we notified ATC of our need to descend. It was during us trying to coordinate a plan with the FA and the FO that I realized the microphone in the oxygen mask was working intermittently. The created an addition challenge with communicating with the crew. We communicated with ATC our intentions to divert. Just a few short moments later we received an ACARS message from dispatch that they noticed we were diverting. We did not respond as we still had a little smoke in the cockpit and where focused on getting down and on the ground. After a fast descent; and around 10;000 ft. I lifted my mask off to see if I could still smell the smoke. I could not and because my mask microphone was working intermittently; we opted to remove our masks to facilitate better communication during the landing phase of flight. Passing through 10;000 ft. we lowered the gear so we could continue our rapid descent. In our haste to keep the descent going it appeared that we went above 250 kts. with the gear extended by 1-2 kts. for 1-2 seconds. We continue the rest of the flight without any more issues. After landing I confirmed with the FA that they did not see any smoke or smell anything. It was at this point that we decided to taxi to the gate. EMB-175 flight crew reported smoke in the cockpit and cabin that resulted in a diversion.